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Docta Complutense author Nogales Díaz, Emilio author Joachimsthaler, I. author Heiderhoff, R. author Piqueras De Noriega, Francisco Javier author Balk, L.J. 2023-06-20T19:01:01Z 2023-06-20T19:01:01Z 2002-07-15 0021-8979 10.1063/1.148744 https://hdl.handle.net/20.500.14352/59111 http://dx.doi.org/10.1063/1.1487440 http://scitation.aip.org/ Near-field cathodoluminescence (NFCL) has been used to characterize hydride vapor phase epitaxy grown n-GaN films. This technique can obtain high resolution luminescence images and perform local measurements of the diffusion length for minority carriers in different parts of the sample. NFCL contrast observed in round growth hillocks at the sample surface, with a diameter of less than 10 mum, is compared with that observed by conventional cathodoluminescence in scanning electron microscope (CLSEM) techniques. In particular NFCL images reveal features not detected by CLSEM which is explained by the fact that under near field conditions the signal arises from a depth of only several tens of nanometers and is then directly related to the surface hillocks. Diffusion lengths of about 0.4 and 4 mum have been found for the holes in different regions of the samples at room temperature. The order of magnitude of these minority carriers diffusion lengths is in good agreement with previous measurements performed at different GaN samples with other techniques. The NFCL contrast and the differences in the measured diffusion lengths are discussed and explained by variations in local trap concentrations. eng Near-field cathodoluminescence studies on n-doped gallium nitride films journal article URL https://docta.ucm.es/bitstreams/8e0bd96c-98b7-4230-bdbc-14daa7d2d5b6/download File MD5 679fdfbc8e4156edfb6c252eccbc425a 295553 application/pdf PiquerasJ39libre().pdf URL https://docta.ucm.es/bitstreams/b86731c2-35ba-43c3-b323-b4554d87466b/download File MD5 e5b0840c0f98bed440831572a548c810 15669 text/plain PiquerasJ39libre().pdf.txt